A. this would need years of practice B. coal, for example, would lose its value C. they could not be stored for years on end D. many products would lose their value 参考答案:D 答案解析:[解析] 文章第三段介绍了货币的价值贮藏职能。该段落大意为:“在物物交换的经济形态中,价值贮藏是难以实现的,在没有统一的价值尺度的情况下,大多数物品都会贬值。”据此可以选D为正确答案。